Hole pitch indicator for drilling bowling ball

ABSTRACT

A pitch indicator for setting up a bowling ball for drilling has a stem portion with an indexing plate pivoted thereto to swing in a plane containing the stem axis. The lower edge of the indexing plate is curved to conform to the curvature of a bowling ball to be drilled, and a center point is marked on the curved edge. With a bowling ball laid out with the usual grip line and the location of the holes marked thereon, the ball is mounted in a cup base on a drilling mechanism. The stem of the indicator is chucked in the drilling machine, and with the curved edge of the plate retained on the grip line, and the center point of the curved edge retained on the laid out center of a hole to be drilled, the ball is moved as required to cause the gauge to read required forward or reverse pitch for that hole. If side pitch is also required, the plate is then turned 90* about the stem axis, and with the center of the curved edge again retained on the hole center, the ball is again moved as required until the gauge indicates the required side pitch. The ball is then locked to its base, the indicator replaced by a drill of required size, and the hole drilled on the laid out hole center.

United States Patent [191 Mai-berg 1 HOLE PITCH INDICATOR FOR DRILLING BOWLING BALL [76] lnventor: Bruce W. Marberg, PO. Box 217,

Bonita, Calif. 92002 221 Filed: Mar. 22, 1972 21 Appl. No.: 237,102

[52] US. Cl. 33/174 F, 33/185 R, 408/DIG. l [51] Int. Cl B23q 3/00, B23b 39/06 [58] Field of Search 33/174 R, 174 F,185, 181;

408/84, DIG. 1

[56] References Cited UNITED STATES PATENTS 3,672,065 6/1972 Voss 33/185 R 2,706,338 4/1955 Ackerman et a1. 33/174 3,521,506 7/1970 Dinardo 408/DIG, 1 2,737,726 3/1956 Christiansen... 33/174 C 2,879,679 3/1959 Neff 408/DIG. 1 3,382,740 5/1968 Lotta 408/D1G. 1 3,329,043 7/1967 Stanford 408/D1G. 1 2,349,394 5/1944 Widdis 408/84 3,349,647 10/1967 Stan 408/DIG. 1

Primary Examiner-John W. Huckert Assistant Examiner-Milton S. Gerstein Apr. 23, 1974 [5 7] ABSTRACT A pitch indicator for setting up a bowling ball for drilling has a stem portion with an indexing plate pivoted thereto to swing in a plane containing the stem axis. The lower edge of the indexing plate is curved to conform to the curvature of a bowling ball to be drilled, and a center point is marked on the curved edge. With a bowling ball laid out with the usual grip line and the location of the holes marked "thereon, the ball is mounted in a cup base on a drilling mechanism. The stem of the indicator is chucked in the drilling machine, and with the curved edge of the plate retained on the grip line, and the center point of the curved edge retained on the laid out center of a hole to be drilled, the ball is moved as required to cause the gauge to read required forward or reverse pitch for that hole. If side pitch is also required, the plate is then turned 90 about the stem axis, and with the center of the curved edge again retained on the hole center, the ball is again moved as required until the gauge indicates the required side pitch. The ball is then locked to its base, the indicator replaced by a drill of required size, and the hole drilled on the laid out hole center.

5 Claims, 4 Drawing Figures HOLE PITCH INDICATOR FOR DRILLING BOWLING BALL BACKGROUND OF THE INVENTION It is customary in drilling the holes for the thumb and selected fingers in a bowling ball to first lay out and mark the location of such holes, together with the grip line to be referred to later herein. For drilling, the ball is set in a cup base which is usually provided with two adjusting screws mounted at right angles to each other for moving the base selected distances along X and Y axes. The base is mounted on the table of a drill press, the axis of the drill press spindle being the Z axis. Pitch index is read in selected fractions of an inch which the ball is moved along the X and Y axes from a position centered on the drill press axis. Complete directions for this prior drilling practice are set forth in a booklet entitled Bowling Ball Drillers ManuallNo. 7-65 published by Ebonite Company, Division of S. W. Industries, Newton, Massachusetts.

Jigs for use in drilling bowling balls are disclosed in U.S. Pat. Nos. 3,262,339 and 3,263,631, and gauges for measuring pitch and grip span of already drilled holes are disclosed in U.S. Pat. Nos. 3,392,453 and 3,429,049.

PURPOSE OF THE INVENTION A primary objective of the present invention is to provide a drill pitch indicator which is chucked in a drill press or other drilling mechanism, and, when applied to a bowling ball mounted on the table of the drill press or drilling mechanism, will read out the pitch of a hole to be drilled in the ball at the indicated center when a drill or bit is substituted for the indicator, the ball locked against rotative movement, and the hole drilled at the indicated center.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objectives and advantages of the invention will be apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of a pitch indicator embodying the invention applied to a bowling ball.

FIG. 2 is an enlarged end view of the indicator.

FIG. 3 is a side elevational view of the indicator.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings in detail, an illustrative pitch indicator A for use in the drilling of a bowling ball comprises a stem portion of circular cross-sectional shape, which may be of rod or tubing, with a pair of flanges 11 and 12 fixedly joined to the stem 10 and preferably integral therewith. The flanges l1 and 12 are parallel to each other and to the axis of the stem 10, and are spaced apart on opposite sides of the stem axis to receive a flat index plate 13 in slidable, bearing relation therebetween. The axis of the stem 10 is thus parallel to, and substantially coincident with the mid-plane of the index plate.

The edge 14 of the indicator plate 13 opposite the stem 10 is curved on a circular arc to conform substantially to the curvature of a selected size of bowling ball to be drilled, and a line 15 extending radially of the center of the curved edge 14 is marked on the face of the indicator plate, with an arrow head 17 preferably 2 marked at its point of intersection. with the curved edge 14.

A circularly curved slot 18 is provided in the index plate 13, with its center of curvature on the radial center line 15. The index plate 13 is mounted for movement in its own plane pivotally about the center of curvature of the slot 18 by a pair of rollers 19 and 20, journaled on pivot pins 21 and 22 spaced equally from the radial center line 15 in FIG. 3. The roller axes define a plane perpendicular to the stem axis and to the index plate 13, and roll easily with minimum clearance in the curved slot 18 so as to move the index plate 13 pivotally about its elected pivotal center, for example, the point of the arrow head 17 in FIG. 3.

Radial gauge lines 23 are marked at selected spaced intervals along the arcuate slot 18 in both directions from the radial center line 15, each gauge line representing relative incremental movement, for example, one-fourth inch, in a direction parallel to the plane of the index plate 13 and perpendicular to the axis of the stem 10, of the center of a bowling ball to which the curved index plate edge 14 is fitted.

Forward and reverse pitch is indicated on the gauge 23 by chucking the pitch indicator stem 10 in the chuck C of a drilling mechanism, such as a conventional drill press, and lowering the chuck C to bring the curved edge 14 coincident with a usual grip line 24', to be referred to later herein, marked on a bowling ball B mounted in a cup base 26 on the table D of the drilling machine. Desired forward or reverse pitch is attained by moving the ball in a selected direction parallel to the plane of the index plate 13 while keeping the arrow head 17 on the marked center point of a hole to be drilled in the ball until the desired forward or reverse pitch is indicated on the gauge 23.

Forward pitch is that wherein the thumb hole inclines toward the finger holes, or the finger holes incline toward the thumb hole, while reverse pitch is that wherein the holes incline in the opposite direction. Side pitch, i.e. right or left pitch relative to the spherical plane of the ball defined by the grip line, is indicated on the gauge 23 by turning the index plate 13 at right angles to the grip line, as by means of the chuck C, and moving the cup base in a selected direction parallel to the new direction of the index plate, in the same manner as described in the preceding paragraph.

In the case of the thumb hole, which is centered on the grip line, right or left pitch is by direct indication on the gauge 23 with the index plate 13 turned to the grip line. However, in the case of the finger holes, which are separated, and ordinarily are located on opposite sides of the grip line, it is necessary to add onehalf inch to the required pitch reading in the direction of the finger hole center from the grip line. This factor is well understood by those familiar with the drilling of bowling balls, but a remainder preferably is printed on the index plate as shown in FIG. 3 so there is no danger of the driller overlooking it.

OPERATION It is assumed that a bowling ball B has been laid out, see FIG. 4, for standard drilling as by means of a conventional layout gauge, not shown, or other suitable means, with usual grip line 24 marking a diametrical plane of the ball through a usual dot 25 or point indicating the center of the top weight of the ball, and perpendicular to the usual serial number 27 engraved on the ball. Also, that the desired location of the thumb hole layout 28 middle finger hole layout 29 and ring finger hole layout 30, including the respective hole centers, are marked thereon.

With the ball thus laid out, the ball is placed in the 5 is chucked I co-axially in the drilling mechanism chuck C, and the chuck is lowered to bring the curved edge 14 of the index plate 13 onto the ball coincident with the grip line 24 marked thereon. While keeping the curved edge 14 coincident with the grip line 24, and the arrow head 17 on the marked center of the thumb hole layout 28, the cup base 26 is moved slidably on the table in a selected direction parallel to the plane of the index plate 13, and the ball B is moved rotatively in its cup until the gauge 23 reads the desired forward or reverse pitch for the hole to be drilled. In the assumed standard grip, this is zero forward/reverse pitch for the thumb hole.

Since a standard grip for a right-handed bowler has /1 inch right hand pitch, the pitch indicator A is then turned 90 about the stem axis by the means of the chuck C, and, with the arrow head 17 centered on the marked center for the thumb hole, the ball is again moved in a selected direction parallel to the plane of the new direction of the gauge plate, and rotatively in its cup around an axis perpendicular to the gauge plate until the gauge 23 reads one-fourth inch right hand pitch.

The ball B is then locked in this position on the cup base 26 by conventional clamp means 31, provided on again position the curved edge 14 coincident with the grip line 24.

With the arrow head 17 retained laterally opposite the center of the layout 29 marked for the middle finger hole, the cup base 26 is moved slidably along the drill press table D, and the ball is moved rotatively in its socket, as explained previously herein for the thumb hole, until the gauge 23 reads three-eighth inch positive pitch. The ball is then locked in this position by the clamp means 31, since no side pitch is specified for the 5 finger holes for a standard grip.

In the event, however, that side pitch should be desired for the finger holes, it may be provided by turning the index plate 90 about the stem axis and proceeding as explained previously herein for the thumb hole, with the exception, however, that one-half inch be added to the reading to allow for the offset of the finger hole from the grip line as mentioned previously herein, and as is customary in prior ball drilling practice.

hole drilled to required depth, in this case 2 34 inches.

Without unlocking the ball from the ball support, the drill for the middle finger hole is replaced in the chuck C by a drill of selected size for the ring finger hole. This latter drill is then centered on the layout center for the ring finger hole, and that hole is drilled to required depth, also 2 5 inches.

The holes are then beveled and smoothed in accordance with usual practice to complete the ball, ready for use.

The invention provides a simple, inexpensive pitch indicator which accurately indicates both forward and reverse, and right and left pitch of each hole to be drilled in a bowling ball and since the stem of the indicator comprises in effect the pointer of the gauge, and is replaced co-axially by the drill itself, each hole is drilled with the assurance that the it will have the exact forward or reverse, and right or left pitch as indicated.

Having thus described what is claimed as new and useful and desire to be secured by US. Letters Patent 1. A hole pitch indicator for mounting in the drill chuck of a drilling mechanism for use in setting up a bowling ball blank for drilling, in selected sequence, each of the holes therein, such ball blank having a grip line and the location of the hole centers marked thereon, said pitch indicator comprising:

a stem shaped for chucking co-axially in such chuck,

an indexing member mounted on the stem for relative tilting movement in a plane containing the stem axis about a pivot point on the stem axis, such pivot point being exposed for positioning upon axially advancing such chuck in which the pitch indicator mounted, on a selected hole center on the surface of a ball blank supported in a position for drilling in such drilling machine,

an element of the indexing member spaced radially from such pivot point in the plane of tilt of the indexing member and located to contact such ball blank upon axial extension of such chuck, thereby to determine the tilt position of the indexing member relative to the stem axis,

an index mark indicating zero pitch when such chuck, with the pitch indicator mounted therein, is advanced to position such pivot point on a hole center located on the grip line of such ball blank with the radially spaced element also on such grip line and the ball blank so positioned that a radius of the ball blank to such hole center is coincident with the stem axis, and

indexing marks on each side of the zero pitch indicating mark in the plane of tilt of the indexing member indicating, in terms of hole pitch, selected movements of such ball blank along the grip line in each direction from such zero pitch indicating position while retaining such pivot point on such selected hole center and the radially spaced element also in contact with such ball blank.

2. A hole pitch indicator as claimed in claim 1 With the ball B thus locked to the cup base 26, the wherein the indexing member is a flat plate.

pitch indicator A is replaced in the chuck C by a drill or bit, not shown, of required size, which is centered on the layout center for the middle finger hole and the 3. A hole pitch indicator as claimed in claim 2 wherein one edge of the indexing plate is concavely curved to conform substantially to the periphery of such ball blank when applied to a surface of the ball blank along a diametrical plane thereof.

4. A hole pitch indicator as claimed in claim 3 wherein the pivotal axis of tilting movement of the indexing plate is located on the curved edge of the plate.

5. A hole pitch indicator as claimed in claim 3 movement along the slot about its center of curvature. 

1. A hole pitch indicator for mounting in the drill chuck of a drilling mechanism for use in setting up a bowling ball blank for drilling, in selected sequence, each of the holes therein, such ball blank having a grip line and the location of the hole centers marked thereon, said pitch indicator comprising: a stem shaped for chucking co-axially in such chuck, an indexing member mounted on the stem for relative tilting movement in a plane containing the stem axis about a pivot point on the stem axis, such pivot point being exposed for positioning upon axially advancing such chuck in which the pitch indicator mounted, on a selected hole center on the surface of a ball blank supported in a position for drilling in such drilling machine, an element of the indexing member spaced radially from such pivot point in the plane of tilt of the indexing member and located to contact such ball blank upon axial extension of such chuck, thereby to determine the tilt position of the indexing member relative to the stem axis, an index mark indicating zero pitch when such chuck, with the pitch indicator mounted therein, is advanced to position such pivot point on a hole center located on the grip line of such ball blank with the radially spaced element also on such grip line and the ball blank so positioned that a radius of the ball blank to such hole center is coincident with the stem axis, and indexing marks on each side of the zero pitch indicating mark in the plane of tilt of the indexing member indicating, in terms of hole pitch, selected movements of such ball blank along the grip line in each direction from such zero pitch indicating position while retaining such pivot point on such selected hole center and the radially spaced element also in contact with such ball blank.
 2. A hole pitch indicator as claimed in claim 1 wherein the indexing member is a flat plate.
 3. A hole pitch indicator as claimed in claim 2 wherein one edge of the indexing plate is concavely curved to conform substantially to the periphery of such ball blank when applied to a surface of the ball blank along a diametrical plane thereof.
 4. A hole pitch indicator as claimed in claim 3 wherein the pivotal axis of tilting movement of the indexing plate is located on the curved edge of the plate.
 5. A hole pitch indicator as claimed in claim 3 wherein the indexing plate is pivotally mounted on the stem by means of a curved slot in the plate having its center of curvature on the curved edge, and means carried by the stem ride in such slot to guide the plate for movement along the slot about its center of curvature. 